Abstract/Description

Tolerance of rice to low temperatures The damages caused to rice crops by low temperatures and cold are reviewed, and crop symptoms are indicated. The results of genetic improvement efforts regarding cold tolerance in rice are also discussed. Low temperatures limit rice production in the tropical and subtropical upland areas of temperate zones. The effects of cold temperatures during different stages of plant development include reduced yields, extended vegetative cycle, and deteriorated grain quality. The nature and extent of the damages caused to the crop will depend, among other factors, on the duration and intensity of the cold spell as well as on the stage of the crop when low temperatures occur. One way to deal with adverse climatic conditions is by using varieties tolerant to this type of stress. Rice improvement programs in the southernmost part of Latin America are selecting germplasm for tolerance to cold conditions at different phenological stages. This is usually done by exposing the germplasm to natural conditions—a methodology that works but is both expensive and time-consuming. The Latin American Fund for Irrigated Rice (FLAR) has recently developed several procedures under controlled conditions to accelerate germplasm selection. This strategy combines the cold tolerance of japonica rice with the yield potential and grain quality of indica rice. This objective has been persistently pursued by different agricultural research organizations in the affected areas. As a result, since 2001 one of FLAR’s programs has focused on combining high yields with cold tolerance to offer useful rice germplasm to its partners in temperate areas of South America, where the cold climate represents an ongoing threat to this crop.